1. Field of the Invention
The present invention relates to a controller such as a set-top box, a digital television receiver and the like, which is connected to an IEEE 1394 serial bus.
2. Description of the Related Art
A conventional controller connected to an IEEE 1394 serial bus (hereafter referred to simply as “bus”) controls target devices, connected to the bus, in accordance with information returned from each target device as a result of an inquiry which the controller makes, by sending an inquiry command, after bus reset occurrence, to each target device to inquire device information of each target device.
However, in the conventional controller as described above, device information needed to control each target device is directly acquired from each target device each time a bus reset is occurred. Accordingly, there is a problem that it takes a long time to acquire device information of all the target devices to be controlled. This problem increases in proportion to the number of target devices for the controller to control.
Meanwhile, Japanese Laid-open Patent Publication 2002-16620 discloses a technology of device connection for devices to be connected to a bus, wherein when there is contention to acquire a channel of bus interface, the channel is switched to a plug with highest priority among plugs in contention. In a technical field of device connection of this kind, furthermore, Japanese Laid-open Patent Publication 2003-18161 discloses a technology to increase the priority of a device associated with a detected event, and to allocate a band by priority to the device with the increased priority. However, none of the technologies disclosed in these patent publications can solve the above-described problem that it takes a long time to acquire device information of all the target devices.